Modern farming practices strive to increase yields of agricultural fields. Yields can be increased by increasing plant populations. Efforts have been made to increase plant populations by planting row crops with narrower row spacing, allowing more rows to be planted in a field, which may require harvesting with special equipment configured for harvesting narrow rows, such as narrow row heads for the harvesting implements. Twin-row planters have been developed that plant seeds as a pair of row segments that are closely width-spaced and longitudinally staggered at every row. Each pair of row segments is spaced from adjacent pairs of row segments at conventional row widths, allowing conventional heads to be used on the harvesting implements. Yet other efforts to increase yield include planting a single field with different seed varieties, based on variations of soil types and management zones such as irrigated and non-irrigated zones in the field.